Hi Lameter,
On Fri, Oct 20, 2017 at 06:35:44AM -0500, Christopher Lameter wrote:
> On Fri, 20 Oct 2017, changbin...@intel.com wrote:
>
> > diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> > index 269b5df..2a960fc 100644
> > --- a/mm/huge_memory.c
> > +++ b/mm/huge_memory.c
> > @@ -501,6 +501,43 @@ void prep_transhuge_page(struct page *page)
> > set_compound_page_dtor(page, TRANSHUGE_PAGE_DTOR);
> > }
> >
> > +struct page *alloc_transhuge_page_vma(gfp_t gfp_mask,
> > + struct vm_area_struct *vma, unsigned long addr)
> > +{
> > + struct page *page;
> > +
> > + page = alloc_pages_vma(gfp_mask | __GFP_COMP, HPAGE_PMD_ORDER,
> > + vma, addr, numa_node_id(), true);
> > + if (unlikely(!page))
> > + return NULL;
> > + prep_transhuge_page(page);
> > + return page;
> > +}
> > +
> > +struct page *alloc_transhuge_page_nodemask(gfp_t gfp_mask,
> > + int preferred_nid, nodemask_t *nmask)
> > +{
> > + struct page *page;
> > +
> > + page = __alloc_pages_nodemask(gfp_mask | __GFP_COMP, HPAGE_PMD_ORDER,
> > + preferred_nid, nmask);
> > + if (unlikely(!page))
> > + return NULL;
> > + prep_transhuge_page(page);
> > + return page;
> > +}
> > +
> > +struct page *alloc_transhuge_page(gfp_t gfp_mask)
> > +{
> > + struct page *page;
> > +
> > + page = alloc_pages(gfp_mask | __GFP_COMP, HPAGE_PMD_ORDER);
> > + if (unlikely(!page))
> > + return NULL;
> > + prep_transhuge_page(page);
> > + return page;
> > +}
> > +
>
> These look pretty similar to the code used for huge pages (aside from the
> call to prep_transhuge_page(). Maybe we can have common allocation
> primitives for huge pages?
>
yes, they are similar to each other, but allocation approaches are much
different.
hugetlbfs alloc page from reserved memory, while thp just directly get page
from page allocator.I think it doesn't make much sense to provide uified api for both of them, because transhuge_page allocation primitives only used within hugetlbfs code. thp allocation is more common as system wide. If Unify them then all the api need 1 more parameter to distinguish what huge page is going to allocate. -- Thanks, Changbin Du
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